The present invention relates to an image apparatus which can see or visualize a fluoroscopy image at real time, and in particular, the present invention relates to a fluoroscopy image apparatus for the purpose of a medical diagnosis.
In recent years, there has been developed a radiation image-taking apparatus or radiography apparatus using a semiconductor image-taking sensor or image sensor in place of X-ray films or imaging plates which have been used in a simple radiography apparatus. There are two types of image sensors. A first type of the image sensor is formed of an X-ray converting layer which converts X-ray into light; photodiode arrays which are arranged in a matrix form right under the X-ray converting layer; and TFT switches connected to the respective photodiode arrays. In the first type of the image-taking sensor, after irradiation of X-ray, the respective TFT switches are sequentially turned on, so that signal charges stored in respective pixels are read out to form an X-ray image.
A second type of the image sensor has radiation sensor arrays formed of converting layer which responds to the radiation to directly output charge signals corresponding to incident dose or amount, and TFT switches are connected to electrodes disposed in a matrix form right under the radiation sensor arrays. In the second type of the image sensor, the respective TFT switches are sequentially turned on at the time of irradiation, so that signal charges stored in respective pixels are read out to form an X-ray image. Hereunder, the first type of the image sensor will be explained.
FIG. 3 and FIG. 4 show a conventional radiation image apparatus of the aforementioned first type. This apparatus is formed of an image-taking sensor or image sensor 1; a gate driver circuit 2 for sequentially taking out charge signals from the respective pixels 14; a readout amplifier 3 for reading the charge signals from the respective pixels 14; and a control circuit 4 for controlling the gate driver circuit 2 and the readout amplifier 3. And, X-ray picture digital data signals from the image sensor 1 are outputted from the readout amplifier 3 to an outside.
In the image sensor 1, the pixels 14 are regularly arranged two-dimensionally, i.e. in the length and breadth directions. The gate driver circuit 2 is driven by a signal from the control circuit 4, so that pulse signals are sequentially sent to the respective pixels 14 from the line direction through gate lines 13. On the other hand, the readout amplifier 3 is driven by a signal from the control circuit 4, so that X-ray picture charge signals in the respective pixels 14 are sequentially read out from the row or columnar direction through readout signal lines 12.
In each pixel 14, there is a photoelectric conversion element 10. Namely, a scintillator emits light in response to an incidence intensity of X-ray, and the emitted light enters into a photodiode to generate a charge signal. At a position located at a side opposite to an X-ray incidence side and corresponding to each pixel 14, a transistor switch, for example, an FET having a signal readout switching function, is arranged two-dimensionally in each pixel 14. By switch pulses from the gate driver circuit 2 through the gate lines 13, the charge signals are read out to the readout amplifier 3 through the readout signal lines 12.
The X-ray picture digital data signals from the image sensor 1 are outputted from the readout amplifier 3 to the outside. However, since the sensitivities of the respective pixels 14 of the image sensor 1 are irregular and there might be defective pixels, a correction processing circuit 5 is generally provided to carry out a correction process, such as a gain correction, and at the same time, the correction processing circuit 5 carries out an offset correction (correction for returning to a zero level when there is no X-ray input). Furthermore, in order to see the X-ray image better, an image processing circuit 6 is provided to carry out an image processing, such as edge enhancement for the X-ray picture digital data signals, or smoothing.
As described above, one X-ray photograph is taken by spending a time, or images are taken at real time in the rate of more than ten images per second.
The conventional fluoroscopy image apparatus is structured as described above, and in the ordinary sequence control, a control section for controlling an entire system is often used as a system which combines a movement control mechanism for an X-ray generator, an X-ray tube, an examination table, a flat panel type image-taking apparatus or the like, and a data collection control mechanism. And, as the system becomes complicated, a possibility of a system failure of the control section for controlling the system to be inoperative becomes higher. For example, in case an operation is performed by using the aforementioned apparatus, the system failure of the control circuit for controlling the system resulting in failure to obtain the X-ray image means losing an important tool for the operation. In this case, there is a task that if only the X-ray generation in the apparatus is possible, a control system of the conventional flat panel type image-taking apparatus might be switched to a mechanism which can individually control, so that the output signal can be taken out to be observed by a general TV monitor.
The present invention has been made in view of the foregoing, and an object of the invention is to provide a fluoroscopy image apparatus, wherein even if a control system is shut down and an X-ray image can not be obtained while operating the apparatus, in case the X-ray generation in the apparatus is possible, the flat panel type image-taking apparatus can be individually operated and an output signal can be taken out, so that the X-ray image can be observed by a general TV monitor.
Further objects and advantages of the invention will be apparent from the following description of the invention.